Pyrotechnical device



Feb. 19, 1952 E. B. HERSHBERG ETAL 2,586,228

PYROTECHNICAL DEVICE Filed May 22, 1944 MN MN Patented Feb. 19, A1952 to the United States of America as represented by the Secretary of War Application May 22, 1944, Serial No. 536,798

The invention described herein may be manufactured and used by or for the Government, for governmental purposes, without the payment to us of any royalty thereon.

This invention relates to devices which produce and are activated by a name, more specifically to demolition igniting devices which are best adapted for their intended purpose when they produce a smooth, silent and timely flame and are waterproof.

Pocket incendiaries and similar demolition devices are exacting in their requirement of a suitable silent igniter. In the ordinary missile and large-size munitions, the usual means for initiating explosion or burning of an incendiary is a percussion primer in which a primary explosive detonant, upon impact by a striker, generally gives off a loud report accompanied by a bright ilash. This type of igniter has objection able characteristics. Although there are certain chemicals and combinations of chemicals which silently produce flame by spontaneous reaction, they have presented difficulties hitherto in forming a simple and compact igniting meansl with necessary safety provisions for application.

An object of this invention is to provide ademolition device having desirable construction features for economical production, reliable performance and eflicient use.

Another object is to provide a pocket incendiary unit which is satisfactorily compact for carrying convenience and secret use.

A further object is to provide an igniter adapted for use in combination with a campact pocket incendiary unit, the igniter being properly timed and silent in its action and being capable of performing its function even after the unit has been immersed in water.

The invention and other objects will be understood from the following description and accompanying drawing.

In the drawing,

Figure 1 illustrates a top view, partly in section, of a pocket incendiary unit embodying principles of the invention.

Figure 2 illustrates an end view of the incendiary unit.

Figure 3 illustrates an enlarged longitudinalA view of the initiating igniter device detached from the incendiaryunit.

Figure 4 illustrates an enlarged longitudinal view of the initiating igniter device in cross section.

Figure 5 illustrates a fragmentary, partly 1ongituclinal and partly cross-sectional view of' a modied form of the invention.

7 Claims. (Cl. 102-90) l, the pocket incendiary un'itcomprises a case I having an attached igniter tube 2i the igniter tube lying contiguously at the sides of the case and being held to the case firmly Referring to Figure by a cemented clip 3. The case I is constructed in two parts, Il and 5, the latter being more shallow. The two parts of the case are made from an inammable material which is not dissolved by hydrocarbon fuel. These parts of the case are economically and satisfactorily made from virgin black cellulose nitrate with an ordinary plasticizer, such as camphor. The larger part of the case, 4, has a small filler hole 6 through which a liquid fuel may be charged. After the case is filled with the fuel, the hole 6 is covered by a small cellulose nitrate disc or cap "I using collodion or cellulose nitrate with acetone as a cement to seal the hole. It is advantageous to use a granula-r aluminum soap gelling agent, first placing the soap in the case before cementing the two parts together, then lling the case through hole B with a fuel, e. g., Stoddard solvent.

On the side of the case where the ignitioninitiating tube is to be attached, that part of the case is -given a depressed form 8. The two parts of the case have flanges 9 where they are brought together, and they are cemented together by collodion or cellulose nitrate mixed with acetone.

The igniter tube 2 is held rmly attached to the case by a cellulose nitrate plastic clip 3 which is also cemented to the case by collodion or cellulose nitrate mixed with acetone.

The incendiary fuel charged into the case I substantially lls the space therein except for a small void of about 5%.

The assembly and operation of the igniter will be described more particularly with reference to Figure 4. This device, in general, has the shape of a pencil or tube. At one end of the igniter tube 2 is disposed or enclosed friction or strikeanywhere match-head I I. A protective thin disc I'2 closure and a needle-point ring pin I3 are in alignment with the match-head I I.

The match-head II may be attached to the point of a readily available ordinary oiiice pin I4, the' headjof the pin beingcemented to a plastic disc f5 which forms the base of the tube. Satisfactory operation has been obtained even in using a match-head from commercial strike-anywhere matches sold for household use. However, to insure more eiicient functioning, a match-head pellet I`I is rmly embedded in a celluloid cement or preferably a cement of glyptal resin and ethyl acetate as a moisture-resistant binder with an added mixture of potassium' chlorate and antimon'y sulfide. preferably about l2 parts of KClOa to 1 part SbSg. The match-head and cement filling are enclosed in a short tubular capsule of which the body I6 and the end discs I2 and I5 are made of cellulose nitrate. This short tubular compartment is fastened to the larger brass tube at shoulder I1 by collodion cement and crimping at I8.

A readily available commercial phonograph needle serves as a firing pin I3. The firing pin I3 is set into a brass block I8' which normally is held against the pressure of a compressed spring I9 by a looped wire 20 under tension acting as a restraining member. The wire 20 is looped through a small hole 2I in a boss end of block I8. A brass washer 22 is disposed on a shoulder of the block I8 to keep the block in a central position with relation to the side of the tube and the spring.

The other end of the looped wire 20 under tension is wound around the stem of a brass screw 23 which is screwed tightly against a lead washer 26 and into a brass plug 25 at the end of the igniter tube opposite the capsule i6.

A brass partitioning plug 26 is interposed between two sections 2a and 2b of tube 2 to act as a base for one end of spring I9 and to furnish support for a glass ampoule 21 in the end section 2a. The partitioning plug 26 has projection 28 and a groove 29 to serve as fastenings to the brass tube 2b and copper tube 2a and for holding the plug in position. Modeling clay, such as Plasticine or equal, is placed in the groove to serve as a plastic sealing 29'. The looped wire 20 is passed through a hole 30 in the partitioning plug 26 and through the clay. Tufts of absorbent cotton, or similar material, are placed at both ends of the glass ampoule compartment to serve as cushioning supports 3I and 32 for the glass ampoule 21 so as to prevent breakage of the glass by normal oraccidental jarring.

The tension wire 20 which acts as a restraining member may be a tinned piano Wire having a diameter of about .0'14 inch. The restraining member may be made of any material and of proper size to withstand the corrosive action for a predetermined length of time.

The glass ampoule or bulb 21 is constructed of a good grade of glass tubing with awall thickness of about .015 to .025 cm. and the corrosive liquid filling of the ampoule is about 0.45 Inl. of a solution consisting in CuCl2.2HzO, distilled water and varied amounts of glycerol, depending on the timing desired. For example, the solution may have a composition of about 15 parts by weight of the cupric chloride dihydrate and about 85 parts by weight of water or contain up to about '14. parts by weight of glycerol with about parts by Weight of the cupric salt and about 16 parts by weight of Water.

A thin pliable strip of metal 33, e. g. brass, passed through a slot 34 located between the ring pin in a restrained position and the matchhead capsule, acts as an additional safety means for preventing the firing pin from piercing the capsule, if by any possibility the firing pin is set4 in motion prematurely. This strip is removed in arming the incendiary.

The holes 35 and 36 located in the brass tube casing of the firing mechanism serve as vent holes for gaseous products of combustion from the ignited match-head. These holes may be left open, or they may be sealed with a small piece of waterproof tape to prevent access of water and dirt into the casing before arming. The ignitable* i screw-head 23 and surrounding the glass ampoule. This latter section 2a may have a Wall thickness of about .005 inch so that it yields to a suiicient pressure of about lbs. per square inch between a persons fingers to cause bending of the tube and a crushing of theglass'ampoule 21, thereby releasing the corrosive liquid contents which contacts and corrodes the restraining Wire member in a predetermined length ofV time. ranging from a period of about 15 minutes to hours.A

For operation, the safety strip 33 is straightened and removed from the slot 34 and the copper tube 2a. surrounding the timing and releasing compartment is pressed until the glass ampoule 21 is broken to release the corroding liquid into contact with the tension wire 2B. The unit r is then planted or thrown where it is intended to cause the incendiary action. After a period predetermined by the strength of the corroding liquid and the corrosion-resistance of the tension wire 20, the wire is broken by corrosion, thus releasing the firing mechanism. Upon the breaking of the tension wire 20, the firing pin I3 is forced by compressed spring I9 to move abruptly toward the capsule and the tip of the match-head contained therein. The sharp needle point of the ring pin I3 pierces the match-head capsule cover I2, then pierces the match-head tip II, causing the match-head to silently ignite and start the burning of the capsule, which in turn immediately starts the burning of the incendiary 4Q; case and its fuel contents.

With suitable materials used for constructing the incendiary case and in formulating the fuel contents, the incendiary produces an intense heat. The ignition takes place with very little friction and mainly by a sharp sheering as the sharp point of the needle penetrates the match-head tip. This type of ignition is very quiet and sure.

The igniting material in the capsule I6 preferably should contain ingredients which ignite nonexplosively and burn in the absence of air.

For construction of the casing, black virgin stock cellulose nitrate is satisfactory, because this material is adequately waterproof, is resistant to carbonaceous fuel and burns in a silent manner tra"4 without a bright flame. The plastic inthe case preferably should contain suflicient pigment or ller to give the plastic a calcined ash content of about .5% to 2%.

A suitable fuel lling for the case is prepared by mixing with gasoline, naphtha or kerosene, a minor proportion of about 5 to 15% by Weight of aluminum soaps which gel the liquid hydrocarbon fuels. Preferred gelling soaps are mixtures of aluminum soaps of fatty acids containing from 8 to about 14 carbon atoms per molecule with aluminum soaps of naphthenic acids. The gel is made advantageously stable if one of the aluminum lsoaps is a soapv of a saturated fatty acid,

. and another component of the mixture is an alu-- Iminum soap of a naphthenic acid or of an unassenze saturated fatty acid. For example, an effective gelling mixture consists in equal parts of aluminum soaps of coconut oil acids or aluminum laurate, aluminum oleate and aluminum naphthenate. It has been found bestto add-the gelling soaps to a high anti-knock gasoline base fuel. The hydrocarbon fuel may contain 'other additives for thickening or altering burning characteristics, such as rubber, resins, thickening polymers, lamp black, wood flour, nitrated cellulose, or cellulose, pyrophoric metal, and ignition accelerators, such as substances which have a low fire point to insure ready ignition when the incendiary is to be used in a cold climate.

While the different members, such as the' delayed timing means, the restraining means, the firing means, and the igniting chemical substance in the capsule have been described as functioning together in a preferred unit, each of these members may be modiedror in some instances be omitted Without disturbing the functioning of the others. For example, the delayed timing maybe omitted by simply unscrewing screw 23 and straightening the end of Wire so that it is free to move and directly release the firing mechanism. Also, in place of a delay element before ignition, the delay element, 'such as a powder train, may follow ignition as in standard types of hand grenade fuses.

In another adaptation of the igniter the capsule i6 is used Without either the matchhead pellet Il or the pin I4 and in lieu thereof the capsule encloses a small glass vial 3l containing a pyrophoric or spontaneously ignitable fluid substance (not shown) such as divinyl acetylene, diethyl zinc, triethyl boron or the like. The glass vial may be cemented inside the plastic capsule with match composition 38 containing a Waterproof binder as in the booster mixture described. When the firing pin I3 pierces the plastic cover of the capsule, it crushes the vial,'and the fluid ignites the match composition 38 which first ignites the capsule which ignites the inflammable case l of the incendiary device. Only about 0.2 to 0.3 cc. of the nuid need be in the vial.

The waterproofed igniter and associated firing mechanism operate with good precision and satisfactory safety in handling. They function particularly well in conjunction with a pocket incendiary but are adapted for other uses, as, for example, in firing smoke munitions, grenades and the like. With the igniting material fully encased until the moment of ignition by the firing pin piercing the plastic cover, the igniting material ismlgept fully protected and can be fired even wh'the unit is completely immersed in water.

It is to be understood that although the invention has been described with reference particularly to the pocket incendiary unit illustrated in the drawing, other modifications come within the spirit and scope thereof.

We claim:

l. An incendiary device comprising a cellulose nitrate case containing an incendiary nuid, a tubular case attached to said cellulose nitrate case having a perforated relatively rigid tubular portion and a relatively deformable tubular portion, a silent igniter device comprising a spring-pressed plunger mounted on a helical spring in said rigid portion, a frangible capsule in said deformable portion containing a corrosive liquid, a corrodable tie means adjacent said capsule and extending into each of said portions for holding said plunger in a compressible condition and a flammable capsule in said rigid portion having a match-head composition therein adapte-,dito be Vfrictionaliy ignited by said plunger when the frangible portion has Vbeen deformed sufficiently toer-usb said frangible capsule and release said corrosive fluid on said tie means. a

2. An incendiary device'. comprising a' cellulose nitrate case containing an' incendiary duid, a tubular cas attached to said cellulose nitrate case having a relatively rigidtubular .portionand a relatively deformable tubular portion, silent igniter comprising a spring-pressed plunger mounted on: a helical spring in said rigid. por'- tion, a 'frangible capsule containing-'a corrosive liquid in said deformable portion, 'a` corrodabl tie means adjacent 'said capsule and extending into each of said portions for holding said plunger in a compressible condition-fand a scond capsule having a pyrphoiic composition therein adapted tov be ignited by' said plunger rupturing said second capsule 'subsequentto they deformable portion being deformed suilici'ently to crush said frangible capsule, and discharge said corrosive fluid 'on said -tie means.

3. An incendiary device comprising a cellulose nitrate case containing an incendiary fluid, a tubular case having a relatively rigid tubular portion and a relatively deformable tubular portion attached to said cellulose nitrate case, a silent igniter comprising a spring-pressed plunger mounted on a helical spring in said rigid portion, a frangible capsuleV containing a corrosive liquid in said deformableportion, a corrod-able tie means adjacent said frangible capsule and extending into each of said portions for holding said plunger in a compressible condition and a capsule having a fluid pyrophoric composition therein adapted to be ignited by said plunger subsequent to the deformable tubular portion being deformed suiiciently to crush said frangible capsule and discharge said corrosive uid on said tie means.

4. An incendiary device comprising a cellulose nitrate case containing an incendiary fluid, a tubular case having a relatively rigid tubular compartment and a relatively deformable tubular compartment attached by flammable means to said cellulose nitrate case. a silent igniter comprising a spring-pressed plunger mounted on a helical spring in said rigid compartment, a frangible capsule containing a corrosive liquid in said deformable portion, a corrodable tie means adjacent said capsule and extending into each of said portions for holding said plunger in a compressible condition and a flammable capsule having a match-head composition therein adapted to be frictionally ignited by said plunger subsequent to the frangible compartment being deformed suiliciently to crush said frangible capsule and discharge said corrosive fluid on said tie means.

5. An incendiary device comprising a cellulose nitrate case containing an incendiary fluid, a tubular case having a relatively rigid tubular compartment and a relatively deformable tubular compartment attached by flammable means to said cellulose nitrate case, a silent igniter comprising a spring-pressed plunger mounted on a helical spring in said rigid compartment, a frangible capsule containing a corrosive liquid in said deformable compartment. a corrodable tie means adjacent said capsule and extending into each of said compartments and in said spring for holding said plunger in a compressible condition and a flammable capsule having a iiuid pyrophoric composition and a match-head composition therein adapted to be frictionally ignited by said plunger subsequent to the deformable compartment being deformed suciently to crush said frangible capsule and discharge said corrosive fluid around said tie means.

6. An incendiary device comprising a cellulose nitrate case containing an incendiary uid, a tubular case having a relatively rigid tubular compartment and a relatively deformable tubular compartment attached by flammable means to said cellulose nitrateA case, a silent igniter comprising a spring-pressed plunger mounted on a helical spring in said rigid compartment, a frangible capsule containing a corrosive liquid in said deformable compartment, a corrodable tie means adjacent said capsule and extending into each of said compartments for holding said plunger in a compressible condition and a flammable capsule having a uid pyrophoric composition therein adapted to become ignited subsequent to the deformable compartment being deformed sufficiently to crush said frangible capsule and discharge said corrosive uid on said tie means.

7. A silent igniter comprising a cellulose nitrate case having a relatively rigid tubular compartment and a relatively deformable portion, a spring-pressed plunger mounted on a helical spring in said rigid compartment, a frangible capsule containing a corrosive formable portion, a corrodable tie means adjacent said capsule and extending into each of CII liquid in said desaid portions for holding said plunger in a compressible condition and a flammable capsule having a match-head composition therein adapted to be frctionally ignited by said plunger subsequent to the deformable portion being deformed suiciently to crush said frangible capsule and discharge said corrosive fluid on said tie means.

EMANUEL B. HERSHBERG.

EVERETT R. COBURN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,484,190 Ray Feb. 19, 1924 1,539,609 Taylor May 26, 1925 1,792,023 Macy Feb. 10, 1931 2,294,415 McBride Sept. 1, 1942 2,314,678 Zint Mar. 23, 1943 2,328,277 Hunt Aug. 31, 1943 liORliIIGrNv PATENTS Number Country Date 13,622 Great Britain June 4, 1914 130,398 Great Britain Aug. 7, 1919 383,322 Great Britain Nov. 17, 1932 453,795 Great Britain Sept. 18, 1936 

